Sunless tanning agents are typically formulated into two types of cosmetic products. Of these, the most traditional is the self-tanning lotion. The imparted benefit is to achieve a skin coloration equivalent to that from basking in the sun. More recently, a second product category has arrived. Therein a sunless tanning agent in small amounts is added to a typical moisturizing lotion. A “glow or shine” is thereby imparted. Glow or shine is a major factor in the appearance of healthy looking skin.
Prominent among the sunless tanning agents is dihydroxyacetone (“DHA” which is also chemically known as 1,3-dihydroxy-2-propanone). DHA, after application, is believed to exert its effect through interactions between its carbonyl group and the amino groups of amino acids and peptides naturally occurring in the hydrolipid pellicle and first layers of the stratum corneum of the skin. These so-called Maillard reactions are believed (see, e.g., Bobin et al., J. Soc. Cosmet. Chem. 35: 255 (1984)) to lead to formation of brown pigments in the skin, thereby giving skin an appearance similar to that of a naturally obtained tan. A number of other sunless tanning agents have been identified, including melanin, mahakanni (eclipta alba), methyl glyoxal, erythrulose, alloxan, 2,3-dihydroxysuccindialdehyde, mixtures thereof, or the like. These agents are believed to work in a similar way as DHA, but typically do yield somewhat of their own unique pigmentation.
Unfortunately, many sunless tanning products available on the market are not stable in that they turn a yellow and/or orange color after application, especially when exposed to UV light. Other sunless tanning products perform poorly and do not quickly impart a noticeable brown color after application. Such poorly performing products do not prevent “tan-happy” consumers from basking in the sun. Products that underperform, therefore, do not protect consumers from the sun's ultraviolet rays.
There is increasing interest to develop compositions and methods for imparting a sunless tan, and especially, compositions that are storage stable. This invention, therefore, is directed to a composition and method that employ a sunless tanning agent as well as an adjuvant for the sunless tanning agent. The composition employs an adjuvant comprising a +6 oxidation state sulfur moiety and, when applied, unexpectedly results in the consumer having skin with a brownish/tan coloration within a consumer acceptable time.
Additional Information
Efforts have been disclosed for making self-tanning cosmetic compositions. In U.S. Pat. Nos. 5,232,688 and 5,612,044, self-tanner compositions with DHA are described.
Other efforts have been disclosed for making self-tanning compositions. In U.S. Pat. No. 5,750,092, compositions with DHA and secondary amines are described.
Still other efforts have been disclosed for making self-tanning compositions. In U.S. Pat. No. 6,231,837, self tanning formulations comprising DHA, polyethoxyglycol and a polyol are described. In U.S. Pat. No. 5,756,075, a self tanning method is disclosed in which a fluid comprising DHA can be mixed with a complimentary fluid comprising specific primary amines.
None of the additional information describes a composition and/or method that yield excellent sunless tanning results whereby the composition and method employ a sunless tanning agent and an adjuvant comprising a +6 oxidation state sulfur moiety.